Process of sizing paper.



Patented July 16, 1912.

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SOLQHON B. WAGG, WILLIAM II.

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- Speciflcationvof Letters main. Patented J uly'16, 1912.

Application filed January 7, 1911. Serial No. 801,838. I

To all whom it may concern:

Be it known that we, SOLOMON R. VVAoo, WILLIAM L. Waco, and James B. WAGG, citizensof the United States, residing at Appleton, in the county of Outagamie and State of Visconsin, have. invented new and useful Improvements in Processes of Sizing Paper, of which the following is a specification. I p

The present invention has reference to iniprovements in paper manufacture, and more especially in or relating to processes of sizmg paper.

. It comprehends, generally, a highly effective and economic sizing process which, when carried out in the manner hereinafter described, results in a very material in-. crease in the tensile'strength of the paper,

and, at the same time, in a, considerable decreasein cost by the 'avoidanceof certain expensive steps or treatments to which the Web is ordinarilysubjected, and the apparatus necessarily employed in connection therewith.

Briefly described, the process may be considered as subjecting the paper material to successive immersion in three-separate baths of size: first, while in the form of wet pulp, it is subjected to a bath of resin size, whereby the pulp is rendered capable of resisting ink and also of resisting moisture to the extent of .permitting it to undergo the next treatment; second,,the web formed-subse quent to the application of the resin size is passed through a solution of commercial acidulated starch, to further increase the tensile strength of the web; and, third, t-he starch sized web is immersed in a bath of animal glue, the previous coating of sizeforming a cheap and solid foundation to which the glue size readily and permanently adheres. The process is essentially of a continuous nature, and the web is dried after each immersion and before being treated in the succeeding bath, the particular charac ter of the drymg entering to a large degree into the inventionand into its practicability and success. a

In the accompanying drawing there is shown diagrammatically and partly in section the preferred embodiment of the apparatus in connection with which the process is worked. The receptacle or device in'which the pulp sheet is subjected .to the initial bath of resin size is not, however, i11us-.

ordinary type or of any preferred trated, since such receptacle or device may semi-soap sizing, containing from 30% to 40% free resin. bein treated with hot water, a milk white solut on is obtained which is applied to the wet pulp just before the latter is formed into a web, the web-forming step being subsequently carried out in any suitable manner. The resinmpregnated web, designated in the drawing by the reference character a, is then led' through the first-drier B, the latter being here shown as comprising a series of steamheated rolls I) over and around which the web is passed. On leaving this drier, the web is drawn through the size'box or tub .C, containing the acidulated' starch solution, and is then passed between the press-rolls 0; During its passage through tub C the web absorbs from 3% to 3J of the starch, and its gain in tensile strength is from 30% to 45%. The web, coated and impregnated in this manner, is then subjected to a second thorough drying action by being passed around the steam-heated rolls (Z that compose the drier D, the coating of size being uninjured, by the high heat of the rolls,

which latter may, therefore, be rapidly revolved, and the sizing being, moreover, substantially invisible. From the second drier,. the web is led to the tub E containing the glue size andis drawn through -the same and subsequently passed. between the pressrolls 6. The coating of glue size is applied, as will be apparent, on top of the starch coating, and hence will fill up and seal any. cracks therein that may have been produced during the second drying step, the glue adhering readily and effectively to the starch, which latter'constitutes a solid foundation or body for the same. Also, the application of the glue size to the previous coating of starch size has the effect of preventing much of the curling and crimping of thei'web that would take place if the glue size were either applied. directly ,to the web or mixed with the starch and the mixture then applied. The amount of glue size taken ,up by the web during its passage through tub E varies from 25 to 23%,- and the total increase in the tensile strength of the web from the time that it leaves the drier B will .be found to vary from 90% to100%. The glue-sized web, as has been proved from actual experiments, cannot be dried by means of steam-heated rolls without great deterioration, owin to the inability of the size to resist the high temperature of said rolls. It becomes necessary, therefore, to resort to a gradual or prolonged final drying at a comparatively low temperature, this final step, in practice, preferably'taking place in a separate room from the room or rooms in' which the treatments above de scribed are carried out. To this end, the drier F is composed of a series of slowly revolving skeleton drums f over and. around which the web passes, the warm air in the room (at a temperature of from- 70 to 90 F), being caused to. circulate freely through the drums by fans or other suitable agitating devices, and being also di- .rected by the same means against the web.

From thefinal drier, the web passes to a reel, (not shown), upon which it is wound in the ordinary manner.

The process above set forth is designed expressly for the production of high grade writing paper, and it may also be employed with equal success in the manufacture of cement bag paper, the efiect of the applications bithe starch and glue size being to completely close the pores of the paper and to render the latter impervious to mois- In that instance, the final ture and air. drier may be of the same type as the driers B and D, though better results are obtained when the skeleton drum drier is employed.

We claim as ourinvention:

1. A triple sizing process for paper material consisting in treating the material while in the form of wet pulp with a solution of resin size; immersing the subsequentlyformed web in a bath of starch size; and

finally immersing. h web thus treated 11 p r t t. glue size.

2. A triple sizingprocess for paper matein the form of wet pulp with a solution of resin size; drying the subsequently formed web; immersing the dried web m a bath of starch size; drying the sized web; immersing saidweb in a separate bath of glue size; and finally drying the web thus treated.

3. A triple sizing process for paper mate- 'rial consisting in treating the material while thus treated to a gradual drying by circu lating a current of warm air therearound.

4. The process of sizing paper material which consists in treating the material while in the form of wet pulp' with a solution of resin size; drying the subsequently- :Eormed web; immersing the dried web in a bath of. starch size; drying the sized web; immersing said web in a separate bath of glue size; and finally in passing the. web thus treated around a series ofplowly revolving skeleton drums through which a current of warm air continuously circulates to subject the web to a prolonged and gradual drying.

In testimony whereof we have hereunto set our hands in presence of tWo subscribing witnesses.

' soLoMoN n. WAGG. WILLIAM L. waee. JAMES B. wAce.

Witnesses:

Umamno E. CLARK, Tnos. B. Rum.

rial consisting in treating the material while 

